Ford Motor has kept the Continental trademark current, he said, even though the name has been out of the Lincoln lineup for more than a decade.
I'd have to look into it and properly source my answer like a good SirO would, but you can have a registered, or UNregistered Trademark. I suspect this is the latter, which is not afforded the same protection at law as the former.
This is likely good for both companies - the media attention will bring two fading names (which are the same, coincidentally...) back into the spotlight. It may help sell a few of them for both.
...but if you're the designer of an icon, I can understand that you'd be upset by copy-cats. Let's not forget how upset Mark Stevenson was when someone ripped off his article once.